• 대한물리치료과학회지
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• 제15권3호
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• pp.55-63
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• 2008

Background : The Purposes of this study were to understand difference between free walking and obstacle over walking through the naked eye and motion analysis device, and to review merits of obstacle walking training as item of functional assessment in clinical situations. Methods : All participants were male and performed 3 types of walking methods: free walking, obstacle over walking with low block(height=10cm, width=8cm), and obstacle over walking with high block(height=20cm, width=8cm). All walking were performed 3 trials respectively. Results : In the naked eye, initial contact with toes occurred more than heel strike in obstacle over walking, and the flexion angle of hip and knee were increased in obstacle over walking. On interpretations though motion analysis device, cadence, gait speed and weight accept were significant statistically(p<.05). Cadence and gait speed were decreased, and weight accept duration was increased in obstacle over walking. Rotation among three pelvic motions was significant statistically(p<.05), flexion among three hip motions was significant statistically(p<.05) and flexion among three ankle motions was significant statistically(p<.05). Rotation and flexion among three ankle motions was significant statistically(p<.05). Conclusion : Both the naked eye and interpretations of the device presented many difference between free walking and obstacle over walking. In overcrossing obstacles, many participants appeared walking strategy by perform initial contact with toes. Knee flexion was most significant statistically(p<.05) in obstacle over walking with 20cm block.

• 자동차안전학회지
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• 제14권4호
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• pp.84-90
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• 2022

With the popularization of autonomous driving technology, safety has emerged as a more important criterion. However, there are no assessment protocol or methods for AES (Autonomous Emergency Steering). So, this study proposes AES assessment protocol and scenario corresponding to collision avoidance Car-to-Car scenario of Euro NCAP in order to prepare for obstacles that appear after the emergency steering of LV (Leading Vehicle) avoiding obstacles in front of. Autoware-based autonomous driving stack is developed to test and simulate scenario in CARLA. Using developed stack, it is confirmed that obstacle avoidance is successfully performed in CARLA, and the AES performance of VUT (Vehicle Under Test) is evaluated by applying the proposed assessment protocol and scenario.

• 한국항공운항학회지
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• 제24권2호
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• pp.25-30
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• 2016

Obstacle defines all fixed and mobile objects, or parts thereof, that are located on an area intended for the surface movement of aircraft or extend above a defined surface intended to protect aircraft in flight or stand outside those defined surfaces and that have been assessed as being a hazard to air navigation. The airspace around airports are maintained free from obstacles so as to permit the intended aeroplane operations at the airports to be conducted safely and to prevent the airports from becoming unusable by the growth of obstacles around the airports. This is achieved by establishing a series of obstacle limitation surfaces or airspace imaginary surfaces that define the limits to which objects may project into the airspace. This is a case study that shows an application of obstacle limitation criteria, which must be maintained free from an critical obstacle, for specific conditions of two airports. For the purpose of the application, aeronautical studies/flight safety influence assessments were used to identify possible solutions and select a solution that is acceptable without degrading aviation safety.

• PNF and Movement
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• 제19권2호
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• pp.287-301
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• 2021

Purpose: Gait training for stroke patients focuses on adjusting to new environments to facilitate outdoor walking. Therefore, the purpose of this study was to identify the effects of various ground obstacle walking combined with treadmill walking on the gait parameters and functional gait ability of chronic stroke patients. Methods: Twenty-four chronic stroke patients were divided into two groups: an experimental group (n = 12) and a control group (n = 12). The experimental group received a combined gait training using various ground obstacle walking and treadmill walking (VGOW) five times/week for four weeks. The control group received traditional treadmill training (TW) five times/week for four weeks. Patients were evaluated using the figure-8 walk test (F8WT) and the Functional Gait Assessment (FGA) before and after each intervention. Results: The ANCOVA results showed that both treatments significantly influenced F8WT steps, F8WT time, and FGA score. The paired t-test results showed a significant improvement in F8WT steps, F8WT time, and FGA score in the experimental group compared to those in the control group. Conclusion: Combined gait training using various ground obstacle walking and treadmill walking can improve gait ability in chronic stroke patients.

• International Journal of Automotive Technology
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• 제8권4호
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• pp.493-504
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• 2007

This paper proposes a stereo vision-based forward obstacle detection and distance measurement method. In general, stereo vision-based obstacle detection methods in automotive applications can be classified into two categories: IPM (Inverse Perspective Mapping)-based and disparity histogram-based. The existing disparity histogram-based method was developed for stop-and-go applications. The proposed method extends the scope of the disparity histogram-based method to highway applications by 1) replacing the fixed rectangular ROI (Region Of Interest) with the traveling lane-based ROI, and 2) replacing the peak detection with a constant threshold with peak detection using the threshold-line and peakness evaluation. In order to increase the true positive rate while decreasing the false positive rate, multiple candidate peaks were generated and then verified by the edge feature correlation method. By testing the proposed method with images captured on the highway, it was shown that the proposed method was able to overcome problems in previous implementations while being applied successfully to highway collision warning/avoidance conditions, In addition, comparisons with laser radar showed that vision sensors with a wider FOV (Field Of View) provided faster responses to cutting-in vehicles. Finally, we integrated the proposed method into a longitudinal collision avoidance system. Experimental results showed that activated braking by risk assessment using the state of the ego-vehicle and measuring the distance to upcoming obstacles could successfully prevent collisions.

• 한국항공운항학회지
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• 제30권1호
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• pp.28-37
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• 2022

Along with the remarkable advances in GNSS technology, SBAS further enhances the accuracy and integrity of GNSS location information and derives improvement in the safety and efficiency of air traffic management from reducing GNSS location errors, induced by passing through the ionosphere and atmosphere, to less than three meters. In this regard, ICAO specifies the standards of SBAS signals and recommends every party to phase in by 2025; and it is foreseeable that SBAS APV-I and CAT-I will be provided in South Korea by its undertaking the development of KASS, a Korean SBAS. The purpose of the study is to design SBAS APV-I procedure on the basis of the runway 15L of Incheon International Airport and conduct obstacle assessment according to PAN-OPS Doc. 8168, focusing on the usability and usefulness of SBAS APV-I. The results show that SBAS APV-I will provide better decision height compared to other PBN RNP approach procedures such as LNAV and Baro-VNAV at the Incheon International Airport.

• 한국항공운항학회지
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• 제22권2호
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• pp.9-15
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• 2014

'Visual segment surface' means a surface that extends from the missed approach point of non precision approaches (or the decision altitude location for approaches with vertical guidance and precision approaches) to the threshold to facilitate the identification of and protection from obstacles in this visual segment of the approach. Validation is the necessary final quality assurance step in the procedure design process, prior to publication. The purpose of validation is the verification of all obstacle and navigation data, and assessment of flyability of the procedure. This paper shows how to apply the protection for the visual segment of the approach procedure, and the results of the validation for visual segment surface conducted at an airport.

• International Journal of Aeronautical and Space Sciences
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• 제6권2호
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• pp.97-109
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• 2005

In this paper, the critical requirement for obstacle awareness and avoidance is assessed with the compliance of the equivalent level of safety regulation, and then the collision avoidance sensor system is presented with the key design parameters for the requirement of the smart unmanned aerial vehicle in low-altitude flight. Based on the assessment of various sensors, small-sized radar sensor is selected for the suitable candidate due to the real-time range and range-rate acquisition capability of the stationary and moving aircraft even under all-weather environments. Through the performance analysis for the system requirement, the conceptual design result of radar sensor model is proposed with the range detection probability and collision avoidance mode is established based on the time-to-collision, which is analyzed by collision scenario.

• 한국태양에너지학회 논문집
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• 제23권4호
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• pp.21-27
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• 2003

The comparative performance of the WAsP in calculating the wind climate in complex terrain has been examined in order to test the predictability of the wind resource assessment computer code in our country. An analysis was carried out of predicted and experimental 10-min averaged wind data collected over 8 months at four monitoring sites in SongDang province, Jeju island, composed of sea, inland flat terrain, a high and a low slope craters. The comparisons show that the WAsP preditions give better agreement with experimental data by adjusting the roughness descriptions, the obstacle list.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1307-1308
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• 2006

국내의 가공 송전선 지지물($60m{\sim}180m$)에는 야간에 항공기의 안전한 운항을 위한 목적으로 태양전지식 LED 항공장애등(LED aviation obstacle light) 및 그 조절장치를 사용하계 되어있다. 항공장애등은 설치되는 지역이 산간지역등과 같은 환경적인 가혹인자에 노출되기 때문에 등구(globe)의 온도충격 및 온도변화에 따른 크랙방지, 자외선에 강한 재질, 투과성이 우수한 재질을 선정하는 것이 중요하다. 따라서 본 평가기술에서는 여러 제품의 엔지니어링 플라스틱에 대하여 장시간 평가시험이 필요한 내후성시험을 통하여 우수한 재질을 선정하여 등구를 제작하여 항공장애등에 적용하고자 한다.